Golf ball

ABSTRACT

A golf ball having controllable flight characteristics and comprised of a standard sized spherical body with surface depressions located in a band extending therearound and the surface portions outside this band having fewer, or no, depressions to decrease the drag on the ball while leaving the lift characteristics substantially the same thereby to cause the ball, for a given striking force, to exhibit directional control.

United States Patent [191 Nepela et al.

l ll June 25, 1974 GOLF BALL [76] Inventors: Daniel A. Nepela, 18960Fernbrook Ct., Saratoga, Calif. 95070; Fred E. Holmstrom, 6520 FallsRiver Dr., San Jose, Calif. 95120 [22] Filed: Oct. 2, 1972 [21] Appl.No.: 294,363

[52] US. Cl. 273/232, 273/183 C [51] Int. Cl A6311 37/14 [58] Field ofSearch 273/232, 213, 199, 235,

[56] References Cited UNITED STATES PATENTS 2,135,210 11/1938 Farrar273/232 FOREIGN PATENTS OR APPLICATIONS 904,785 8/1962 Great Britain273/213 Primary Examiner-George J. Marlo Attorney, Agent, or Firm-GeraldL. Moore [57] ABSTRACT A golf ball having controllable flightcharacteristics and comprised of a standard sizedl spherical body withsurface depressions located in a band extending therearound and thesurface portions outside this band having fewer, or no, depressions todecrease the drag on the ball while leaving the lift characteristicssubstantially the same thereby to cause the ball, for a given strikingforce, to exhibit directional control.

5 Claims, 5 Drawing Figures mu 1 9 l 8 3 PATENTEDJUNZSIHM FIG. 2

Fics.4

FIG.5

GOLF BALL BACKGROUND OF THE INVENTION This invention relates to animprovement in a golf ball having as its primary purpose the making of agolf ball that will travel substantially the same distance as aconventional ball while giving the player more control over thedirection the ball travels.

Golf balls used today comprise a spherical body made of a solidresilient material. The outer layer of the ball is dimpled to formdepressions to increase the lift forces imparted on the ball when it ishit. When properly struck, the ball will rise in flight and spin about ahorizontal axis such that the bottom of the ball moves in the directionof flight and the top moves opposite to the direction of travel.imparting lift to the ball requires that a film of air immediatelyadjacent the ball surface spins with the ball. This air film at the topof the ball is moving in the same direction as the air passing over theball and thereby serves to increase the velocity of the air at thatpoint. Thus the air pressure at the top surface of the ball is lowerthan elsewhere on the ball. At the same time the air film at the bottomof the ball is reacting against the ambient air flow in a manner to slowthe passing air and increase the pressure at that point. The result is agreater atmospheric pressure at the bottom of the spinning ball than atthe top, thereby supplying a lifting force tending to carry the ballfarther.

As a golf club impacts with a conventional golf ball on the ground, oron a tee, two effects occur. (I) The ball acquires translationalvelocity in the intended direction, and (2) the ball spins about an axisof rotation. The direction the axis of spin takes, or is'given withrespect to the ground and the amount of spin imparted to the ball arethe primary factors in determining what, if any, additional range may beacquired by the ball or whether it will hook or slice upon leaving theclub.

In general, the lifting force increases if the ball spins faster duringflight. However, the spin speed imparted to the ball is substantiallyconstant for each golf club and a given tee height. An important factoraffecting the lift is the thickness of the boundary film of air spinningwith the ball. To increase this thickness, dimples or depressions areformed in the ball surface which cause localized areas of turbulence.Turbulence tends to increase the thickness of the air film spinning withthe ball thereby increasing the lifting forces imparted on the ball.

However, a negative effect is realized also when a dimpled surface isutilized. The force tending to slow a conventional ball as it travelsthrough the air is commonly referred to as drag. The drag isproportional to the planar area of the ball pushing through the air.With the air film spinning with the ball, the effective planar area ofthe ball is increased thereby increasing the drag forces imparted on theball. Naturally any detrimental forces acting to slow the ball in flightwill reduce the distance the ball travels. I

One other detrimental effect of increasing the lift of the ball occurswhen the ball is hit imperfectly, which act results all too often withthe average golfer. In hitting the ball, if the club face is nottraveling in the same direction it is desired for the ball to take,i.e., with the planar surface normal to that direction, a sidewise spinis imparted to the ball causing forces to act thereon similar to thoseimparting lift. In this manner the ball is forced to one side or theother of the intended flight path resulting in a curved flight commonlycalled a hook or slice depending on the direction of the spin. Somegolfers more expert at the game use an intentional hook or slice toimprove theirgame, but most golfers attempt to hit the ball straight forbest results.

It is the primary objective of this invention to provide a golf ballwith substantially the same range as a conventional ball butincorporating a depression design on the surface of the ball that can beoriented on the tee, or with respect to the axis of spin, so that as theball spins in flight, the lift, hook or slice properties of the ball areinfluenced.

SUMMARY OF THE INVENTION A golf ball including a cover having thedepressions therein centered adjacent a single plane passing through thegeometric center of the ball in a manner to affect the air flow past theball during flight and render control over the direction of flight ofthe spinning ball.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows a prior art golf ballhaving the surface depressions distributed evenly over the totalsurface;

FIG. 2 is a view along the lines 2-2 of FIG. 1;

FIG. 3 shows one preferred embodiment of the invention wherein dimpletype depressions are positioned in a band about a circumferential lineextending around the ball;

FIG. 4 shows another preferred embodiment of the invention wherein thesurface depressions comprise grooves extending through a band portionabout the ball; and

FIG. 5 shows still another embodiment wherein the total ball surface isdimpled, however, the density of the dimples is increased within acenter band extending around the ball.

DESCRIPTION OF PREFERRED EMBODIMENTS In FIG. 1 is shown an example of acommonly used golf ball comprising a spherical body 10 of resilientmaterial with the surface thereof having formed therein a plurality ofevenly distributed and spaced depressions or dimples 11 provided toincrease the lift on the spinning ball in flight in the mannerpreviously described. Thus if the ball is travelling in the direction ofthe arrow 12 the natural back spin imparted to the ball at the impact ofthe club (not shown) and the ball will be in the direction of the arrow13 about a spin axis 14 extending out of the plane of the drawing.

Referring now to FIG. 2, the ball of FIG. 1 is shown spinning in adirection with the surface being seen travelling downward relative tothe drawing and with the ball travelling in a direction into the paper.The spin axis is shown as the dotted line 14 extending through thegeometric center of the ball.

To illustrate the net atmospheric force tending to lift the ball, twoarrows are drawn extending in a direction normal to the ball surface.Arrow 15 illustrates a lifting force acting on the bottom of the balland resulting from the interaction of the film of air spinning with theball as heretofore described. Arrow 16 illustrates a downward pressureimparted in the ball having a smaller force (as shown by the length ofthe arrow) than the lifting force thereby resulting in a resultant forceacting to move the ball upward in the manner previously described.

At the same instant, all the surface is being acted on by atmosphericpressure with the differences being that the total forces have lesseffect on the flight of the ball than do those acting on a central bandabout the center of the ball.

For instance, arrow 17 representing a force acting at a point close tothe intersection of the ball surface and the spin axis is comprised offorce arrows 18 and 19. The vertical arrow 18 indicates a slight liftingforce on the ball but unfortunately most of the force consists of thatindicated by the arrow 19 acting to push the ball to the side because ofthe location of the point at which the force acts. Of course, thesidewise direction force 19 is offset by another force acting in theopposite direction on the other side of the ball. Additionally the totalforce acting at this point is less than those nearer arrow since theball surface velocity, and therefore the velocity of the air filmtravelling with the surface, is less than that at arrow 15.

However, the air film over the total surface is nearly uniform inthickness due to the even distribution of the dimples in the ballsurface. The thickness of the air film adds to the overall drag area ofthe ball thereby contributing to the drag forces imparted on the ballthus tending to slow it down while in flight. The air film in the polarregions about the spin axis contribute to the drag while contributinglittle or nothing to the overall lift imparted on the ball.

In accordance with the present invention, the dimples or surfacedepressions on the ball surface are concentrated in a circumferentialband centered about a circumferential line around the ball. If the ballis teed with the plane of the band aimed along the desired direction offlight, the lift characteristics of the ball remain substantiallyunchanged over a conventional ball since, as shown heretofore, thoseareas external to the circumferential band contribute little to the liftimparted on the ball when spinning about the axis 26.

By making the surface regions outside the bar d smoother, i.e. fewerdimples, less air turbulence results and a thinner film of air iscarried by these areas thereby reducing the drag on the ball while notappreciably affecting the lift forces. In this manner, the lift to dragratio of the ball is adjusted upward.

As shown in FIG. 3, a preferred embodiment of the ball of the subjectinvention includes a standard resillent body 20 as used in prior artdevices. However dimples 21 are concentrated in a band extending aboutthe sphere and centered about an imaginary plane represented by thedotted line 22 passing through the geometric center of the ball. Thepolar regions 24, and 25 are relatively smooth surfaced in thisembodiment. Of course the ball could also be made with the surfacedepressions being more pronounced within the band but of equal densityas those outside the band.

The subject ball is teed in the position shown with the band extendingin a vertical plane in the direction of the intended flight of the ball.Upon being hit, the ball spins about the spin axis 26 extending throughthe midpoints of the polar regions 24 and 25. Lift of the ball isaccomplished by the air film adjacent the dimpled band. However, only athin air film spins adjacent to the regions 24 and 25 due to thesmoother surface configuration. Thus the lift exerted on the ball issubstantially the same as for the prior art ball since the areas of highlift are the same. However the drag on the ball is decreased becauseless air film is carried with the ball.

A further and more unexpected result occurs with the ball heretoforedescribed and shown in FIG. 3. If by chance the ball is hit with asidewise spin, which commonly causes a hooking or slicing direction oftravel, the resulting sidewise spin will result in less curving of theflight path since less lift results from the regions 24 and 25. Thusmore control over the ball is provided by the subject invention.

Tests have shown that if the ball is hit with a partial sidewise spin,the subject ball will first start the curved flight commonly called thehook or slice. The path of the ball will thereafter tend to straightenout on a line close to the intended path and cease following thecurving, or arcuate, path originally caused by the sidewise spin. Onefurther factor tending to cause this unexpected result may be theslightly greater weight at the polar regions of the ball because of thelesser density of the dimples on the ball surface. Thus, the ballexhibits what can best be described as a barbell effect; that is, theball always attempts to spin about a longitudinal axis extending throughboth polar regions. As a result, the sidewise spin ceases as the ballcorrects itself in flight, thereby doing away with the sidewise spinwhich otherwise would cause further curving of the flight path.

Upon landing, the ball will assume any of a number of positions relativeto the green where it is ultimately desired to be positioned. Howeverthe shots following the tee shot usually have distance as a secondaryrequirement and if the ball is not aligned to provide maximum lift,little effect results. The ball will always have an equal amount ofdimples and less dimpled surface area to each side of a plane passingthrough the geometric center and perpendicular to the spin axis suchthat little or no curving of the flight path results from an unalignedlie. Further, if the barbell effect does in fact correct the sidewisespin, the ball will soon assume a spin about an axis perpendicular tothe axis of the dimpled band. The player need only allow for less liftif the band initially does not align with the flight path. For putting,the undimpled areas between dimples form an even spherical surface forcontrol of the ball.

In FIG. 4 is shown another embodiment of the ball wherein the inventionis incorporated in a ball 27 having central band 28 of depressions. Thedepressions are formed by a series of grooves 29 extending from onesmooth region 30 to the other smooth region 31. The ridges 32 combinewith the grooves to create turbulence thereby to increase the film ofair spinning with the ball as did the depressions in the previousembodiment.

FIG. 5 illustrates still another embodiment of the invention wherein theball 34 has dimples 35 distributed over the total surface area. Howeverin this instance the dimples are within a center band indicated by lines36 and 37. Thus the turbulence within this band is greatest therebyincreasing the thickness of the film adjacent thereto, while thatadjacent to the cap regions 38 and 39 is less thick. Thus, control ofthe ball is increased in the same manner as in previous embodiments withsimilar beneficial results.

We claim:

1. A golf ball including a cover having a plurality of depressions atspaced locations on the surface thereof adapted to exert a lifting forceon the ball as it spins during flight, and said depressions beinglocated to cause greater surface air turbulence adjacent a singlecircumferential band extending around the ball thereby to affect the airflow therearound and render control over the direction of flight of theball as the ball spins about an axis generally perpendicular to theplane of the band during flight.

2. A golf ball as defined in claim 1 wherein said surface depressionsare dimples in the ball surface.

3. A golf ball as defined in claim 1 wherein said surface depressionsare positioned in a circumferential 10 but those within the band areshaped to cause a greater air turbulence than those outside the band.

1. A golf ball including a cover having a plurality of depressions atspaced locations on the surface thereof adapted to exert a lifting forceon the ball as it spins during flight, and said depressions beinglocated to cause greater surface air turbulence adjacent a singlecircumferential band extending around the ball thereby to affect the airflow therearound and render control over the direction of flight of theball as the ball spins about an axis generally perpendicular to theplane of the band during flight.
 2. A golf ball as defined in claim 1wherein said surface depressions are dimples in the ball surface.
 3. Agolf ball as defined in claim 1 wherein said surface depressions arepositioned in a circumferential band extending around the ball surfaceand centered about the circumferential line.
 4. A golf ball as definedin claim 3 wherein depressions are located on the ball surface at placesother than within the band but spaced farther apart than those withinsaid band.
 5. A golf ball as defined in claim 3 wherein the depressionsare located both within and outside the band but those within the bandare shaped to cause a greater air turbulence than those outside theband.